1. Technical Field of the Invention
The present invention relates to the administration of bacterial extracts cultured in thermal water for the care of sensitive skin and/or scalps.
2. Description of Background and/or Related and/or Prior Art
Human skin is made up of two compartments, namely, a deep compartment, the dermis, and a surface compartment, the epidermis.
The epidermis is in contact with the external environment. One of its roles consists in protecting the body from dehydration and from external aggressions, especially linked to environmental factors of irritant or pollutant type (detergents, pollution, cigarette smoke, etc.), mechanical stresses (friction, abrasion, shaving, frequent washing, etc.), thermal or climatic imbalances (cold, wind, dryness, UV radiation, etc.), xenobiotics (microorganisms, allergens, etc.), cosmetic or dermatological chemical treatments (peeling, anti-acne treatment, etc.), or by physiological factors (age, stress, etc.).
Certain individuals have skin or a scalp that is more sensitive than others.
Generally, sensitive skin is defined by a particular reactivity of the skin. However, as opposed to skin that is qualified as allergic, this reactivity is not a matter of an immunological process, that is to say, does not occur only on skin that is already sensitized in response to the presence of an allergen. Its mechanism is said to be a specific.
This skin reactivity is conventionally expressed by the manifestation of signs of discomfort in response to contact of the subject with a triggering element which may have various origins. It may be the application of a cosmetic product to the surface of sensitive skin, the intake of food, the exposure to sudden temperature variations, to atmospheric pollution and/or to ultraviolet or infrared rays. There are also associated factors such as age and skin type. Thus, sensitive skin is more frequent among dry or greasy skin than among normal skin.
The appearance of these signs of discomfort, which appear in the minutes which follow the contact of the subject with the triggering element, is one of the main characteristics of sensitive skin. These are mainly dysesthesic sensations. The term “dysesthesic sensations” means more or less painful sensations that are felt in an area of the skin such as sensations of stinging, tingling, itching or pruritus, burning, hotness, discomfort, tautness, etc. These subjective signs usually exist in the absence of visible chemical signs such as redness and desquamations. It is known today that these skin irritation and intolerance reactions are especially linked to a release of neuropeptides by the nerve endings of the epidermis and of the dermis.
The exhibitions of sensitive skin or scalps in the meaning of the invention appear without any inflammatory reaction. It is known that inflammation is characterized by the four simultaneous clinical signs (robor, calor, dolor, tumor) which are not present the phenomenon of sensitive skin or scalps; in particular, there is no swelling (tumor) and the dysesthesic sensations, although uncomforting, could not be called painful.
For obvious reasons, the absence of visible signs makes the diagnosis of sensitive skin difficult. Usually, this diagnosis relies on taking a history from the patient. This symptomology moreover has the advantage of making it possible to differentiate sensitive skin associated or not with dry skin, from contact irritation or allergy for which there are, on the other hand, visible inflammatory signs.
Consequently, the development of “sensitive skin” products has made it necessary to use tools for evaluating the sensory reaction of the skin. The first tools were based, right from their design, on the essential feature of dry skin, namely, the presence of signs of discomfort induced by a topical application. Thus, the lactic acid “stinging test” was the first test proposed. It was carried out by recording the stinging sensations reported by a volunteer after application of a 10% lactic acid solution to the wings of the nose. The subjects reporting moderate or strong stinging sensations were referred to as “stingers” and considered to have sensitive skin. Due to this sensitivity of the skin to the topical application of a product, these subjects were then selected to test “sensitive skin” products. More recently, in order to specifically activate the peripheral nerve endings involved in the discomfort and known as nociceptors, recently identified as being involved in sensitive skin, new tests have been proposed which precisely use other inducers of discomfort such as capsaicin.
This second type of test, described in EP 1 374 913, also constitutes another tool that is particularly useful for the diagnosis of sensitive skin.
Within the meaning of the present invention, sensitive skin covers irritable skin and intolerant skin.
Intolerant skin is skin which reacts by sensations of hotness, tautness, tingling and/or redness, to various factors such as the application of cosmetic or dermatological products or of soap. In general, these signs are associated with erythema and with a hyperseborrhoeic or acneic skin, or even skin exhibiting rosacea, with or without dry patches.
Irritable skin is skin which reacts via pruritus, that is to say, via itching or via stinging, to various factors such as the environment, emotions, foods, wind, friction, shaving, hard water with a high calcium concentration, temperature variations or wool.
Usually, irritability of the skin is expressed by visible signs such as redness of the skin, a feeling of hotness of the skin or of the scalp (heat) which may extend to a feeling of pain.
“Sensitive” scalps have a more univocal clinical symptomology: the sensations of itching and/or of stinging and/or of hotness are mainly triggered by local factors such as friction, soap, surfactants, hard water with a high calcium concentration, shampoos or lotions. These sensations are also sometimes triggered by factors such as the environment, emotions and/or foods. An erythema and a hyperseborrhoea of the scalp and also a dandruff condition are frequently associated with the preceding signs.
Thus, need remains for novel compositions that make it possible to prevent and/or treat the symptoms of sensitive mucous membranes, scalps and skin.